An absorbent article, such as a disposable diaper and a sanitary napkin, has an absorber for absorbing body fluid discharged by a wearer. Generally, the absorber is formed of an absorber core made of ground pulp, superabsorbent polymer (SAP), and the like, and of a cover material that is made of tissue and the like and that covers the absorber core (see PTL 1, for example).
Specifically, in a manufacturing process of the absorber, firstly, ground pulp is prepared by grinding a pulp sheet with a grinder. Subsequently, the ground pulp is mixed with superabsorbent polymer while passing through a supply duct, and thereby a powder mixture is formed.
A drum-type absorber forming and transferring mechanism collects the powder mixture to form absorber cores, and then places the absorber cores at predetermined intervals on a first web being conveyed and including cover materials. A second web including further cover materials is placed on the web having the absorber cores placed thereon.
Thereafter, a continuous absorber web formed of the first and second webs with the absorber cores interposed therebetween is cut in the cross direction (CD) perpendicular to the conveyance direction (machine direction MD) of the absorber web, and thereby the absorbers are manufactured.
Forming recesses are made at predetermined intervals on the outer circumferential surface of the absorber forming and transferring mechanism. The forming recesses collect the powder mixture constantly blown out from a blowing device and thus form the absorber cores. A bottom portion of each of the forming recesses is provided with multiple suction holes attracting the powder mixture.
The inventors have discovered that when the powder mixture is constantly blown out from the blowing device, it adheres to portions other than the forming recesses (such as convex portions) on the outer circumferential surface of the absorber forming and transferring mechanism. As a result, a certain amount of the powder mixture is wasted, and thereby the cost of manufacturing the absorbers is increased.
To reduce the waste of the powder mixture, it is considered to narrow intervals between the multiple forming recesses formed in the outer circumferential surface of the absorber forming and transferring mechanism. However, if the intervals between the multiple forming recesses are narrowed, the intervals between the absorber cores placed on the web are also narrowed.
In contrast, in order to place the absorber cores at predetermined intervals on the web, the intervals between the multiple forming recesses formed in the outer circumferential surface of the absorber forming and transferring mechanism (i.e., the size of each convex portion) need to be widened. Therefore, a certain amount of the powder mixture is inevitably wasted.